On Wed, May 09, 2012 at 10:21:04AM +0200, Richard Guenther wrote:
> Using the stmt UID looks odd as you are using it as flag - why not use
> one of the two stmt flags available to passes?
>
> Btw, the other possibility would be to simply change the various combiners
> to require them to update the iterator to point at the first statement that
> they have inserted. I have some TLC ideas in this area, let's see if I can
> get to them.
>
> Ok with using gimple_set_plf and friends.
Here is what I've committed after doing another bootstrap/regtest:
2012-05-09 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/53226
* tree-ssa-forwprop.c (ssa_forward_propagate_and_combine): Remove
prev and prev_initialized vars, gimple_set_plf (stmt, GF_PLF_1, false)
before processing it and gimple_set_plf (stmt, GF_PLF_1, true) if it
doesn't need to be revisited, look for earliest stmt with
!gimple_plf (stmt, GF_PLF_1) if something changed.
* gcc.c-torture/compile/pr53226.c: New test.
--- gcc/tree-ssa-forwprop.c.jj 2012-05-03 08:35:52.000000000 +0200
+++ gcc/tree-ssa-forwprop.c 2012-05-08 18:10:19.662061709 +0200
@@ -2677,8 +2677,7 @@ ssa_forward_propagate_and_combine (void)
FOR_EACH_BB (bb)
{
- gimple_stmt_iterator gsi, prev;
- bool prev_initialized;
+ gimple_stmt_iterator gsi;
/* Apply forward propagation to all stmts in the basic-block.
Note we update GSI within the loop as necessary. */
@@ -2771,12 +2770,14 @@ ssa_forward_propagate_and_combine (void)
/* Combine stmts with the stmts defining their operands.
Note we update GSI within the loop as necessary. */
- prev_initialized = false;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
{
gimple stmt = gsi_stmt (gsi);
bool changed = false;
+ /* Mark stmt as potentially needing revisiting. */
+ gimple_set_plf (stmt, GF_PLF_1, false);
+
switch (gimple_code (stmt))
{
case GIMPLE_ASSIGN:
@@ -2856,18 +2857,18 @@ ssa_forward_propagate_and_combine (void)
{
/* If the stmt changed then re-visit it and the statements
inserted before it. */
- if (!prev_initialized)
+ for (; !gsi_end_p (gsi); gsi_prev (&gsi))
+ if (gimple_plf (gsi_stmt (gsi), GF_PLF_1))
+ break;
+ if (gsi_end_p (gsi))
gsi = gsi_start_bb (bb);
else
- {
- gsi = prev;
- gsi_next (&gsi);
- }
+ gsi_next (&gsi);
}
else
{
- prev = gsi;
- prev_initialized = true;
+ /* Stmt no longer needs to be revisited. */
+ gimple_set_plf (stmt, GF_PLF_1, true);
gsi_next (&gsi);
}
}
--- gcc/testsuite/gcc.c-torture/compile/pr53226.c.jj 2012-05-08
18:07:40.007000510 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr53226.c 2012-05-08
18:07:35.071029578 +0200
@@ -0,0 +1,13 @@
+/* PR tree-optimization/53226 */
+
+void
+foo (unsigned long *x, char y, char z)
+{
+ int i;
+ for (i = y; i < z; ++i)
+ {
+ unsigned long a = ((unsigned char) i) & 63UL;
+ unsigned long b = 1ULL << a;
+ *x |= b;
+ }
+}
Jakub
